Solid state lighting devices with dielectric insulation and methods of manufacturing

ABSTRACT

Solid state lighting devices and associated methods of manufacturing are disclosed herein. In one embodiment, a solid state lighting device includes a first semiconductor material, a second semiconductor material spaced apart from the first semiconductor material, and an active region between the first and second semiconductor materials. The solid state lighting device also includes an indentation extending from the second semiconductor material toward the active region and the first semiconductor material and an insulating material in the indentation of the solid state lighting structure.

TECHNICAL FIELD

The present technology is directed generally to solid state lighting(“SSL”) devices with dielectric insulation and associated methods ofmanufacturing.

BACKGROUND

SSL devices generally use semiconductor light emitting diodes (“LEDs”),organic light emitting diodes (“OLEDs”), laser diodes (“LDs”), and/orpolymer light emitting diodes (“PLEDs”) as sources of illuminationrather than electrical filaments, a plasma, or a gas. FIG. 1 is across-sectional diagram of a portion of a conventional indium galliumnitride (“InGaN”) LED 10. As shown in FIG. 1, the LED 10 includes asubstrate material 12 (e.g., silicon carbide, sapphire, or silicon), anN-type gallium nitride (“GaN”) material 14, an active region 16 (e.g.,GaN/InGaN multiple quantum wells (“MQWs”)), and a P-type GaN material 18on top of one another in series. The LED 10 can also include a firstcontact 11 on the P-type GaN material 18 and a second contact 15 on theN-type GaN material 14.

The GaN/InGaN materials 14, 16, and 18 of the LED 10 are generallyformed via epitaxial growth. The formed GaN/InGaN materials 14, 16, and18, however, typically include a high density of lattice dislocationsthat can negatively impact the optical and/or electrical performance ofthe LED 10. For example, as described in more detail later, the formedGaN/InGaN materials 14, 16, and 18 can include a plurality ofindentations that may form unintended carrier passages bypassing theactive region 16 during processing.

One conventional technique for addressing the high density of latticedislocations is to incorporate aluminum nitride (AlN), silicon nitride(SiN), and/or other suitable interlayers in the LED 10 (e.g., betweenthe substrate 12 and the N-type gallium nitride 14). The incorporationof such interlayers, however, cannot completely eliminate the latticedislocations in the GaN/InGaN materials 14, 16, and 18 of the LED 10.Also, incorporating interlayers adds cost and time to the manufacturingprocess of the LED 10. Accordingly, several improvements to at leastlessen the impact of the lattice dislocations in LEDs may be desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a portion of an LED in accordancewith the prior art.

FIG. 2A is a cross-sectional view of a portion of a microelectronicsubstrate undergoing a process for forming an SSL device in accordancewith embodiments of the technology.

FIG. 2B is a cross-sectional view of a portion of a microelectronicsubstrate undergoing a process for forming an SSL device in accordancewith conventional techniques.

FIGS. 2C-2F are cross-sectional views of a portion of a microelectronicsubstrate undergoing a process for forming an SSL device in accordancewith embodiments of the technology.

FIGS. 3A-3F are cross-sectional views of a portion of a microelectronicsubstrate undergoing another process for forming an SSL device inaccordance with additional embodiments of the technology.

DETAILED DESCRIPTION

Various embodiments of SSL devices with dielectric insulation andassociated methods of manufacturing are described below. The term“microelectronic substrate” is used throughout to include substratesupon which and/or in which SSL devices, microelectronic devices,micromechanical devices, data storage elements, read/write components,and other features are fabricated. The term “lattice dislocation”generally refers to a crystallographic defect or irregularity within acrystal structure. A lattice dislocation can include a V-defect, an edgedislocation, a threading (or screw) dislocation, and/or a combinationthereof. A person skilled in the relevant art will also understand thatthe technology may have additional embodiments, and that the technologymay be practiced without several of the details of the embodimentsdescribed below with reference to FIGS. 2A and 2C-3F.

FIGS. 2A and 2C-2F are cross-sectional views of a portion of amicroelectronic substrate 100 undergoing a process for forming an SSLdevice in accordance with embodiments of the technology. The SSL devicecan be an LED, an OLED, a LD, a PLED, and/or other suitable devices. Inthe following description, common acts and structures are identified bythe same reference numbers. Even though only particular processingoperations and associated structures are illustrated in FIGS. 2A and2C-2F, in certain embodiments, the process can also include forming alens, a mirror material, support structures, conductive interconnects,and/or other suitable mechanical/electrical components (not shown).

As shown in FIG. 2A, an initial operation of the process can includeforming an SSL structure 101 and an optional buffer material 103 on asubstrate material 102. The substrate material 102 can include a silicon(Si) wafer (e.g., with a Si(1,1,1) crystal orientation), aluminumgallium nitride (AlGaN), GaN, silicon carbide (SiC), sapphire (Al₂O₃), acombination of the foregoing materials, and/or other suitable substratematerials. In certain embodiments, the optional buffer material 103 caninclude AlN, GaN, zinc nitride (ZnN), and/or other suitable materials.In other embodiments, the optional buffer material 103 may be omitted,and the SSL structure 101 may be formed directly on the substratematerial 102.

The SSL structure 101 can include a first semiconductor material 104, anactive region 106, and a second semiconductor material 108 stacked oneon the other. In one embodiment, the first and second semiconductormaterials 104 and 108 include an N-type GaN material and a P-type GaNmaterial, respectively. In another embodiment, the first and secondsemiconductor materials 104 and 108 include a P-type GaN material and anN-type GaN material, respectively. In further embodiments, the first andsecond semiconductor materials 104 and 108 can individually include atleast one of gallium arsenide (GaAs), aluminum gallium arsenide(AlGaAs), gallium arsenide phosphide (GaAsP), gallium(III) phosphide(GaP), zinc selenide (ZnSe), boron nitride (BN), AlGaN, and/or othersuitable semiconductor materials.

The active region 106 can include a single quantum well (“SQW”), MQWs,and/or a bulk semiconductor material. As used hereinafter, a “bulksemiconductor material” generally refers to a single grain semiconductormaterial (e.g., InGaN) with a thickness greater than about 10 nanometersand up to about 500 nanometers. In certain embodiments, the activeregion 106 can include an InGaN SQW, InGaN/GaN MQWs, and/or an InGaNbulk material. In other embodiments, the active region 116 can includealuminum gallium indium phosphide (AlGaInP), aluminum gallium indiumnitride (AlGaInN), and/or other suitable materials or configurations.

The SSL structure 101 and the optional buffer material 103 can be formedon the substrate material 102 via MOCVD, molecular beam epitaxy (“MBE”),liquid phase epitaxy (“LPE”), hydride vapor phase epitaxy (“HVPE”),and/or other suitable epitaxial growth techniques. It has been observed,however, that the SSL structure 101 formed via the foregoing techniquestypically includes a high density of lattice dislocations. For example,as shown in FIG. 2A, the SSL structure 101 can include a plurality ofindentations 110 in the SSL structure 101. Three indentations 110 areshown in FIG. 2A for illustration purposes, and the dimensions of theindentations 110 are exaggerated for clarity.

As shown in FIG. 2A, the indentations 110 can include a plurality ofsidewalls 111 extending into the SSL structure 101. In the illustratedembodiment, the indentations 110 individually include sidewalls 111extending from a surface 108 a of the second semiconductor material 108into the active region 106 and the first semiconductor material 104. Inother embodiments, at least some of the indentations 110 can includesidewalls that extend only into the active region 106, or theindentations can extend into the optional buffer material 103 or eveninto the substrate material 102. In any of the foregoing embodiments,the SSL structure 101 can also include edge dislocations, threadingdislocations, and/or other lattice dislocations (not shown).

Without being bound by theory, it is believed that various structuraland/or operational conditions may cause the formation of theindentations 110 during processing. For example, it is believed thatindentations 110 may form due to different crystal growth rates alongdifferent crystal facets of the substrate material 102 (or the optionalbuffer material 103). It has been observed that epitaxial growth alongcertain crystal facets (e.g., c-plane) results in lower surface energythan other crystal facets (e.g., m-plane). As a result, epitaxial growthmay propagate along certain crystal facets faster than others to formthe indentations 110. It is also believed that contaminant particles onthe surface of the substrate material 102 and/or other epitaxial growthconditions may also cause the indentations 110 to form.

The indentations 110 can cause low optical efficiencies of the SSLstructure 101 when the microelectronic substrate 100 is processed inaccordance with conventional techniques. For example, as shown in FIG.2B, a conductive material 112 (e.g., silver) is formed on the secondsemiconductor material 108 as an electrical contact in accordance withconventional techniques. The conductive material 112 includes a firstportion 112 a on the surface 108 a of the second semiconductor material108 and a second portion 112 b in contact with the first semiconductormaterial 104. Thus, the second portion 112 b of the conductive material112 forms carrier passages 113 electrically connecting the first andsecond semiconductor materials 104 and 108. As a result, charge carriers(i.e., holes and electrons) from the first and second semiconductormaterials 104 and 108 may bypass the active region 106 and combinenon-radiatively in the carrier passages 113. Such non-radiativerecombination can thus cause low optical efficiencies in the SSLstructure 101.

Several embodiments of the process can at least reduce or eliminate therisk of forming bypassing carrier passages 113 by incorporating aninsulation material in the SSL structure 101. As shown in FIG. 2C,another operation of the process includes depositing an insulatingmaterial 118 on the SSL structure 101. The insulating material 118 caninclude a first insulating portion 118 a on the surface 108 a of thesecond semiconductor material 108 and a second insulating portion 118 bin the indentations 110. In the illustrated embodiment, the insulatingmaterial 118 generally conforms to the surface 108 a and the sidewalls111 of the indentations 110. In other embodiments, the insulatingmaterial 118 can partially or substantially fill the indentations 110,as described in more detail later with reference to FIG. 2F.

The insulating material 118 can include silicon dioxide (SiO₂), siliconnitride (SiN), hafnium silicate (HfSiO₄), zirconium silicate (ZrSiO₄),hafnium dioxide (HfO₂), zirconium dioxide (ZrO₂), aluminum oxide(Al₂O₃), and/or other suitable materials with a dielectric constanthigher than about 1.0 at 20° C. under 1 kHz. Techniques for forming theinsulating material 118 can include chemical vapor deposition (“CVD”),atomic layer deposition (“ALD”), spin-on coating, thermal oxidation,and/or other suitable techniques.

FIG. 2D shows another operation of the process, in which the firstinsulating portion 118 a (FIG. 2C) of the insulating material 118 isremoved from the SSL structure 101 while the second insulating portion118 b remains in the indentations 110. As a result, the insulatingmaterial 118 does not cover the surface 108 a of the secondsemiconductor material 108. In one embodiment, removal of the firstinsulating portion 118 a is stopped when the surface 108 a of the secondsemiconductor material 108 is exposed. In other embodiments, at least aportion of the second semiconductor material 108 may be removed beyondthe surface 108 a. Techniques for removing the first insulating portion118 a of the insulating material 118 include chemical-mechanicalpolishing (“CMP”), electro-chemical-mechanical polishing (“ECMP”), wetetching, drying etching, laser ablation, and/or other suitable materialremoval techniques.

FIG. 2E shows a subsequent operation of the process, in which aconductive material 120 is formed on the SSL structure 101 with theinsulating material 118. As shown in FIG. 2E, the conductive material120 includes a first conductive portion 120 a and a second conductiveportion 120 b. The first conductive portion 120 a is in contact with thesurface 108 a of the second semiconductor material 108 forming anelectrical contact for the SSL structure 101. The second conductiveportion 120 b is within the indentations 110 and in contact with thesecond insulating portion 118 b.

In certain embodiments, the conductive material 120 can include indiumtin oxide (“ITO”), aluminum zinc oxide (“AZO”), fluorine-doped tin oxide(“FTO”), and/or other suitable transparent conductive oxide (“TCOs”). Inother embodiments, the conductive material 120 can include copper (Cu),aluminum (Al), silver (Ag), gold (Au), platinum (Pt), and/or othersuitable metals. In further embodiments, the conductive material 120 caninclude a combination of TCOs and one or more metals. Techniques forforming the conductive material 120 can include MOCVD, MBT, spraypyrolysis, pulsed laser deposition, sputtering, electroplating, and/orother suitable deposition techniques.

The SSL device formed in accordance with several embodiments of theforegoing process can have improved optical efficiencies overconventional devices by eliminating bypassing carrier passages 113 (FIG.2B). For example, as shown in FIG. 2E, the second insulating portion 118b electrically insulates the second conductive portion 120 b from theactive region 106 the first semiconductor material 104. The secondinsulating portion 118 b can thus prevent the second conductive portion120 b from forming carrier passages that would otherwise bypass theactive region 106 by directly connecting the first and secondsemiconductor materials 104 and 108. As a result, non-radiativerecombination of charge carriers (i.e., holes and electrons) inbypassing carrier passages can be at least reduced or generallyeliminated in the SSL structure 101.

Even though the insulating material 118 is shown as generally conformalto the SSL structure 101 in FIGS. 2C-2E, in certain embodiments, theinsulating material 118 can also have other configurations. For example,as shown in FIG. 2F, the second portion 118 b of the insulating material118 can substantially or completely fill the indentations 110, thesecond portion 118 b of the insulating material 118 can even extendbeyond the surface 108 a of the second semiconductor material 108.Subsequently, portions of the insulating material 118 that extend beyondthe surface 108 a may be removed via CMP, ECMP, and/or other suitabletechniques. Thus, the second insulating portion 118 b can be generallycoplanar with the surface 108 a of the second semiconductor material108. In other examples, the insulating material 118 can partially fillthe indentations 110 and/or have other suitable configurations. Infurther examples, the insulating material 118 may be formed beforeforming the second semiconductor material 108, as described in moredetail below with reference to FIGS. 3A-3E.

FIGS. 3A-3E are cross-sectional views of a portion of a microelectronicsubstrate 100 undergoing another process for forming an SSL device inaccordance with additional embodiments of the technology. As shown inFIG. 3A, an initial operation of the process can include forming a firstsemiconductor material 104 and an active region 106 on a substratematerial 102 (with an optional buffer material 103) via MOCVD, MBE, LPE,HVPE, and/or other suitable epitaxial growth techniques. The activeregion 106 has a surface 106 a facing away from the first semiconductormaterial 104.

As described above with reference to FIG. 2A, it is believed thatvarious structural and/or operational conditions may cause the formationof indentations 210 (three are shown for illustration purposes) duringepitaxial growth, as shown in FIG. 3A. In the illustrated embodiment,the indentations 210 have a plurality of sidewalls 211 extending fromthe surface 106 a of the active region 106 into the first semiconductormaterial 104. In other embodiments, at least some of the indentations210 can also have sidewalls extending into the optional buffer material103 and/or the substrate material 102.

As shown in FIG. 3B, another operation of the process includesdepositing the insulating material 118 on the microelectronic substrate100 such that the first insulating portion 118 a is on the surface 106 aof the active region 106 and the second insulating portion 118 b is inthe indentations 210. As shown in FIG. 3C, the process can furtherinclude removing the first insulating portion 118 a (FIG. 3B) of theinsulating material 118 from the microelectronic substrate 100 in afashion generally similar to that described above with reference to FIG.2D. The material removal operation may be stopped when the surface 106 aof the active region 106 is exposed while the second insulating portion118 b remains in the indentations 210.

As shown in FIG. 3D, a subsequent operation of the process includesforming the second semiconductor material 108 on the microelectronicsubstrate 100 via MOCVD, MBE, LPE, HVPE, and/or other suitable epitaxialgrowth techniques. The first semiconductor material 104, the activeregion 106, and the second semiconductor material 108 form a differentembodiment of the SSL structure 101. In one embodiment, the secondsemiconductor material 108 may grow into the indentations 210 via acombination of lateral and vertical growth. Thus, the secondsemiconductor material 108 includes a first semiconductor portion 108 aon the surface 106 a of the active region 106 and a second semiconductorportion 108 b in the indentations 210. In other embodiments, theindentations 210 may be filled with a filler material (e.g., AlN, notshown) before the second semiconductor material 108 is formed. Infurther embodiments, the second semiconductor material 108 may haveother suitable configurations. In any of the foregoing embodiments, thesecond insulating portion 118 b of the insulating material 118electrically insulates the second semiconductor material 108 from thefirst semiconductor material 104 and the active region 106.

In the illustrated embodiment, the second semiconductor material 108 hasa generally planar surface 108 a facing away from the active region 106.As shown in FIG. 3E, another operation of the process can includeforming a conductive material 120 on the generally planar surface 108 afor electrical connection to the second semiconductor material 108. Inother embodiments, the second semiconductor material 108 can also have anon-planar surface (not shown) and/or have other suitable structuralconfigurations.

FIG. 3F shows another embodiment of the process in which the secondinsulating portion 118 b of the insulating material 118 cansubstantially fill the indentations 210, which can be generally similarto the operation described above with reference to FIG. 2E. In theillustrated embodiment, the insulating material 118 is generallycoplanar with the surface 106 a of the active region 106. In otherembodiments, the insulating material 118 can be non-planar with thesurface 106 a and/or have other suitable configurations.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. Many of the elements of one embodiment may be combined withother embodiments in addition to or in lieu of the elements of the otherembodiments. Accordingly, the disclosure is not limited except as by theappended claims.

1. A solid state lighting device, comprising: a first semiconductormaterial; a second semiconductor material spaced apart from the firstsemiconductor material; an active region between the first and secondsemiconductor materials, the active region including at least one of anindium gallium nitride single quantum well, gallium nitride (GaN)/indiumgallium nitride (InGaN) multiple quantum wells, and an InGaN bulkmaterial; a conductive material in contact with the second semiconductormaterial; and an insulating material electrically insulating at least aportion of the first semiconductor material from the conductivematerial.
 2. The solid state lighting device of claim 1 wherein: thesecond semiconductor material has a surface facing away from the activeregion; the solid state lighting device includes an indentationextending from the surface of the second semiconductor material into thefirst semiconductor material through the active region; the indentationhas sidewalls extending from the surface of the second semiconductormaterial into the active region and the first semiconductor material;the insulating material is in the indentation and generally conforms tothe sidewalls of the indentation; the conductive material includes afirst portion and a second portion; the first portion of the conductivematerial is on the surface of the second semiconductor material; thesecond portion of the conductive material is in the indentation and incontact with the insulating material; and the insulating materialelectrically insulates the active region and the first semiconductormaterial from the second portion of the conductive material.
 3. Thesolid state lighting device of claim 1 wherein: the second semiconductormaterial has a surface facing away from the active region; the solidstate lighting device includes an indentation extending from the surfaceof the second semiconductor material into the first semiconductormaterial through the active region; the indentation has sidewallsextending from the surface of the second semiconductor material into theactive region and the first semiconductor material; the insulatingmaterial is in contact with the sidewalls of the indentation; theinsulating material generally fills the indentation and is generallycoplanar with the surface of the second semiconductor material; theconductive material is in contact with the surface of the secondsemiconductor material and the insulating material in the indentation;and the insulating material electrically insulates the active region andthe first semiconductor material from the conductive material.
 4. Thesolid state lighting device of claim 1 wherein: the active region has asurface facing away from the first semiconductor material; the solidstate lighting device includes an indentation extending from the surfaceof the second semiconductor material into the first semiconductormaterial through the active region; the indentation has sidewallsextending from the surface of the active region into the firstsemiconductor material; the insulating material is in the indentationand generally conforms to the sidewalls of the indentation; the secondsemiconductor material includes a first semiconductor portion and asecond semiconductor portion; the first semiconductor portion of thesecond semiconductor material is on the surface of the active region;the second semiconductor portion of the second semiconductor material isin the indentation and in contact with the insulating material; thesecond semiconductor material has a generally planar surface facing awayfrom the active region; the conductive material is in contact with thegenerally planar surface of the second semiconductor material; and theinsulating material electrically insulates the first semiconductormaterial from the second semiconductor material and the conductivematerial.
 5. The solid state lighting device of claim 1 wherein: theactive region has a surface facing away from the first semiconductormaterial; the solid state lighting device includes an indentationextending from the surface of the second semiconductor material into thefirst semiconductor material through the active region; the indentationhas sidewalls extending from the surface of the active region into thefirst semiconductor material; the insulating material is in contact withthe sidewalls of the indentation; the insulating material generallyfills the indentation and is generally coplanar with the surface of theactive region; the second semiconductor material is in contact with thesurface of the active region and the insulating material in theindentation; the second semiconductor material has a generally planarsurface facing away from the active region; the conductive material isin contact with the generally planar surface of the second semiconductormaterial; and the insulating material electrically insulates the firstsemiconductor material from the second semiconductor material and theconductive material.
 6. The solid state lighting device of claim 1wherein: the solid state lighting device further includes an indentationextending between at least one of the first semiconductor material andthe second semiconductor material, the first semiconductor material andthe active region, and the active region and the second semiconductormaterial; and the insulating material is in the indentation.
 7. Thesolid state lighting device of claim 1 wherein: the solid state lightingdevice further includes an indentation extending between at least one ofthe first semiconductor material and the second semiconductor material,the first semiconductor material and the active region, and the activeregion and the second semiconductor material; the indentation has agenerally V-shaped cross-section; and the insulating material is in theindentation.
 8. The solid state lighting device of claim 1 wherein: thesolid state lighting device further includes an indentation havingsidewalls extending between at least one of the first semiconductormaterial and the second semiconductor material, the first semiconductormaterial and the active region, and the active region and the secondsemiconductor material; and the insulating material is in theindentation and generally conforms to the sidewalls of the indentation.9. The solid state lighting device of claim 1 wherein: the secondsemiconductor material has a surface facing away from the active region;the solid state lighting device further includes an indentation havingsidewalls extending from the surface of the second semiconductormaterial toward the first semiconductor material via the active region;the insulating material is in the indentation and generally conforms tothe sidewalls of the indentation; and the insulating material is not onthe surface of the second semiconductor material.
 10. The solid statelighting device of claim 1 wherein: the second semiconductor materialhas a surface facing away from the active region; the solid statelighting device further includes an indentation having sidewallsextending from the surface of the second semiconductor material towardthe first semiconductor material through the active region; theinsulating material is in the indentation and generally conforms to thesidewalls of the indentation; and the conductive material is in contactwith the surface of the second semiconductor material and with thesidewalls of the indentation.
 11. The solid state lighting device ofclaim 1 wherein: the second semiconductor material has a surface facingaway from the active region; the solid state lighting device furtherincludes an indentation having sidewalls extending from the surface ofthe second semiconductor material toward the first semiconductormaterial through the active region; the insulating material is in theindentation and generally conforms to the sidewalls of the indentation;the insulating material is not on the surface of the secondsemiconductor material; and the conductive material is in contact withthe surface of the second semiconductor material and with the sidewallsof the indentation.
 12. A solid state lighting device, comprising: asolid state lighting structure having: a first semiconductor material; asecond semiconductor material spaced apart from the first semiconductormaterial; an active region between the first and second semiconductormaterials; an indentation extending from the second semiconductormaterial toward the active region and the first semiconductor material;and an insulating material in the indentation of the solid statelighting structure.
 13. The solid state lighting device of claim 12wherein: the second semiconductor material has a surface facing awayfrom the active region; and the indentation extends from the surface ofthe second semiconductor material into at least the active region. 14.The solid state lighting device of claim 12 wherein: the secondsemiconductor material has a surface facing away from the active region;and the indentation extends from the surface of the second semiconductormaterial into the first semiconductor material through the activeregion.
 15. The solid state lighting device of claim 12 wherein: theactive region has a surface facing away from the first semiconductormaterial; the indentation extends from the surface of the active regioninto the first semiconductor material; the solid state lighting devicefurther includes a conductive material in contact with the secondsemiconductor material; and the insulating material is between theconductive material and the active region and between the conductivematerial and the first semiconductor material.
 16. The solid statelighting device of claim 12 wherein: the active region has a surfacefacing away from the first semiconductor material; the indentationextends from the surface of the active region into the firstsemiconductor material; and the insulating material is between the firstand second semiconductor materials and between the active region and thesecond semiconductor material.
 17. A solid state lighting device,comprising: a solid state lighting structure having: a firstsemiconductor material; a second semiconductor material spaced apartfrom the first semiconductor material; an active region between thefirst and second semiconductor materials; and an insulating material ina discrete area of the solid state lighting structure, the insulatingmaterial being in contact with and covering at least a portion of theactive region of the solid state lighting structure.
 18. The solid statelighting device of claim 17 wherein the insulating material is incontact with and covers at least a portion of the active region and atleast a portion of the first semiconductor material.
 19. The solid statelighting device of claim 17 wherein: the insulating material is incontact with and covers at least a portion of the active region and atleast a portion of the first semiconductor material; the secondsemiconductor material includes a surface facing away from the substratematerial; and the insulating material does not cover the surface of thesecond semiconductor material.
 20. The solid state lighting device ofclaim 17 wherein: the second semiconductor material includes a surfacefacing away from the active region; the solid state lighting structureincludes an indentation extending from the surface of the secondsemiconductor material toward the active region; and the insulatingmaterial generally conforms to the indentation of the solid statelighting structure.
 21. A method for forming a solid state lightingdevice, comprising: forming a solid state lighting structure on asubstrate material, the solid state lighting structure having: a firstsemiconductor material; a second semiconductor material spaced apartfrom the first semiconductor material; an active region between thefirst and second semiconductor materials; and an indentation extendingat least partially between the second semiconductor material and thefirst semiconductor material; forming an electrical contact on thesecond semiconductor material with a conductive material; andelectrically insulating the conductive material from at least one of theactive region and the first semiconductor material.
 22. The method ofclaim 21 wherein: the second semiconductor material has a surface facingaway from the active region; and the indentation has sidewalls extendingfrom the surface of the second semiconductor material into the activeregion; and electrically insulating the conductive material includesinterposing an insulating material between the conductive material andthe active region and between the conductive material and the firstsemiconductor material.
 23. The method of claim 21 wherein: the secondsemiconductor material has a surface facing away from the active region;and the indentation has sidewalls extending from the surface of thesecond semiconductor material into the active region; and electricallyinsulating the conductive material includes depositing an insulatingmaterial in the indentation prior to forming the electrical contact. 24.The method of claim 21 wherein: the second semiconductor material has asurface facing away from the active region; and the indentation hassidewalls extending from the surface of the second semiconductormaterial into the active region; and electrically insulating theconductive material includes at least partially filling the indentationwith an insulating material prior to forming the electrical contact. 25.The method of claim 21 wherein: the second semiconductor material has asurface facing away from the active region; and the indentation hassidewalls extending from the surface of the second semiconductormaterial into the active region; and electrically insulating theconductive material includes: depositing an insulating material on thesolid state lighting structure, the insulating material including afirst insulating portion on the surface of the second semiconductormaterial and a second insulating portion in the indentation; andremoving the first insulating portion of the insulating material fromthe surface of the second semiconductor material, the second insulatingportion remaining in the indentation; and forming an electrical contactincludes depositing the conductive material on the surface of the secondsemiconductor material and the second insulating portion of theinsulating material.
 26. The method of claim 21 wherein: the secondsemiconductor material has a surface facing away from the active region;and the indentation has sidewalls extending from the surface of thesecond semiconductor material into the active region; and electricallyinsulating the conductive material includes: depositing an insulatingmaterial on the solid state lighting structure, the insulating materialincluding a first insulating portion on the surface of the secondsemiconductor material and a second insulating portion in theindentation and generally conforming to the sidewalls of theindentation; and removing the first insulating portion of the insulatingmaterial from the surface of the second semiconductor material, thesecond insulating portion remaining in the indentation; and forming anelectrical contact includes depositing the conductive material on thesurface of the second semiconductor material and the second insulatingportion of the insulating material.
 27. The method of claim 21 wherein:the second semiconductor material has a surface facing away from theactive region; and the indentation has sidewalls extending from thesurface of the second semiconductor material into the active region; andelectrically insulating the conductive material includes: depositing aninsulating material on the solid state lighting structure, theinsulating material including a first insulating portion on the surfaceof the second semiconductor material and a second insulating portion inthe indentation; and removing the first insulating portion of theinsulating material from the surface of the second semiconductormaterial, the second insulating portion remaining in the indentation andgenerally filling the indentation; and forming an electrical contactincludes depositing the conductive material on the surface of the secondsemiconductor material and the second insulating portion of theinsulating material.
 28. The method of claim 21 wherein: the activeregion has a surface facing away from the first semiconductor material;and the indentation has sidewalls extending from the surface of theactive region into the first semiconductor material; and forming a solidstate lighting structure includes: depositing an insulating material onthe solid state lighting structure, the insulating material including afirst insulating portion on the surface of the active region and asecond insulating portion in the indentation; and removing the firstinsulating portion of the insulating material from the surface of theactive region, the second insulating portion remaining in theindentation; and subsequently, forming the second semiconductor materialon the active region and the second insulating portion of the insulatingmaterial.